Boss for dobby jacks



y 28, 1953 E. c. JOHNSON 2,

' soss'm DOBBY JACKS Filed July 18, 1951 Patented July 28, 1953 BOSSFOR- DOBBY JACKS Emil Johnson, Manchesten. Conn assignortov H. F.Liverm'ore Corp0ratio n,. Allston, Mass a.

corporation of Delaware Applicatiomluly 1 8, 1951, Serial N 0., 2313,44;

9 Claims. (Cl. 139-74) 1 This invention relates to dobby; motions inlooms, and more particularly to dobby jacks.

In a common form of dobby motion the hooks. controlled by the patternchai-ntransmit the moticn imparted to them by the knives to the dobbyjacks through jack-backs which. are pivotally connected to the jacks bybosses formed, integrally on the jacks. These bosses project into thecenter bearings of the jack-backs and are made-of length or. siah-thumbin he; ckness of the jack-backs, sothat the jacks; canbepositioned close together side by side for com paetness inthe dobbyhead; reliance being placed solely on the next adjacent jack to hold;the inte vening jack-hack in placev on its pivot. Since sufficientclearance must be given to. allow the individual jacks to move freelywith respect to other in response to the demands of the pattern, thejfiCkr-bEtCKSLBJBJ able to. deviate way from their proper jacksQutw-ardly onthebosses;v forming their pivots, with the result; thatthe, bosses: wear most. rapidly toward their outward ends. departingfromv their desired cylindrical form andr-ounding, off their outer;edges onwhich the. wear concentrates; in. an oblique manner whichresults in lost motion depriving the jack of itsintended scope ofmovement, and; also camming the jack-back sidewise into. interferenceandv jamming contact, with. the; adjacent jack, impairing, the lattersfreedom: of movement. Since thesebosses are conventionally an integralportion of they castin comprising the jaclgg. this wear; of the bossesordinarily compels discarding replacing. of the entirejack. A repair-'-has. been proposed consisting oi; machining andzd'rill'r. ing the bossto make possible the. installation ofv a stud-like boss; usually made ofbronze, rigidly and: non-rctatably riveted to the jack, which at:bestisonly aqteniporary. expedient, asitgis subject to-the samewealmessesoi; rapid wear andLjammingiof'the adjacent jacks, particularlyon heavy loads of harnesses, where it sometimes wears. out in a weeksuse. 7

In both these. cases, addition-ally; Wear of the center bearing of thejack-back which rides on the boss occurs becauseef the relative rotationof the boss surface within such bearing, evenwally-requiring replacementof the jack-back also. 1 r 1.

An. important object: of the. invention therefore is toienable; a jack.which hasabeen/rendered un. usable through wear ofthe integral bossinitially. r ed; er-nontoe p r d. and: ont ued. in

'use; by removing the bossthereon.

2 I a. replacement boss. of simple and compact propprtionswhichembodiesfew partsand yet.is -.c n.-. structed so; that wear throughengagementwith he jack-each is not, concentrated, ononeportion of, theouter rim toround off its. edges or to diminish its working diameter, but isdistributed uniformly around the boss.

Another object of the invention is to provide a boss capable ofsupporting greater load than heretofore and at thev same time to;increase the life-of. the jack.

A further I object is toprovide a. boss which; will largely eliminate orreduce to a. negligible. degree thewear of the center bearing of; thejack-back incident to its. pivotalmounting on; the jack.

To thesevends; I have; devised a novel replaces of the jack-back andplaced on; the stud androll; being distributed evenly around" the entiresurface-of the roll. Whentheroll finally rou h. ens. 5 ar ow to: n mpner size fit itcan easily bereplaced by an ideni a s thou h n c s ty of;discard naand replacing, the jaelnwhich itself-is a source of 'l i iiillustrative; embodiment of. the, device is shown: in the accompanyingdrawings; in which. 1; is-an elevation: of a portion-ofa (lobby jackShowing the roll. and mountingstud com.- prisi-ng the nevelhoss: fixed.thereon.

Fig. 2 is a section online-Q-Zof Fig-1.

Figs. Sandi-a showthe stud in section, illustrating, successive: stages:in; the; manufacture of the stud.

steel roll having a central; aperture 2 which fits rotatahly aboutthecylindrical'surface I4 of the head 4. of a stud; ifixed the'jack; lever8. Roll; I is retained in place on the head ei the; stud reasonofaninwardly extendingannular flange Ii which fits about a neck portionti-of the head i oi the stud which is of reduced diameter interveningbetween the full diameter head; 4 andsthe, shank]. 0fthe,stud. Thisbossis applied towthe j ack lever at thesamelocation as that.

5.5.01 the origi al in e ral oss. te med. thereon...

For this purpose, the center of the original boss is spotted and a holeIii drilled through the jack concentric therewith, of the proper size toreceive the shank 1 of stud 5, and countersunk at its extremity remotefrom the boss, and thereafter the remainder of the old boss is groundoff flush with the adjacent surface of the jack.

The stud is most securely fixed to the jack 8 by being riveted thereto,and for this purpose the shank I is made soft enough for heading overand also provided with a conical recess l2 faciliating the expansion ofthe end of the shank into the countersunk extremity of hole In asindicated in Fig. 2, while avoiding the formation of a protruding headat this surface of the jack lever. The roll I is made to fit closelywithin the hub or bearing provided at midlength of the jack-back (notshown) for its connection to the jack lever. But in accordance with theinvention and contrary to the practice with the integral boss, this rollis not intended to have relative movement within the hub or hearing ofthe jackback; instead, all or most of the relative motion is intended tooccur at the bearing surfaces comprised by the interior surface ofaperture 2 of the roll and the opposing cylindrical surface M of thestud 5.

To attain a long life of the boss, provision must be made for preparingthese bearing surfaces to endure their mutual contact, and because theboss is in novel manner made in two parts, it becomes simple inaccordance with the invention to prepare these surfaces to receive suchwear, by the step of hardening them. Thus, the entire roll I is hardenedas a unit wholly apart and away from the stud, by any suitable ordesired known hardening process. The stud presents a different problem,since its shank 1 must be left soft and malleable to provide for beingriveted in place in jack 8. However, by coating the entire surface of astud made of low carbon steel with a layer I6 of resist, as shown inFig. 3, which for one example is effected sim ply by copper-plating thestud, and then grinding off such resist from the cylindrical surface ofthe head t of the stud to leave the underlying component steel of thesurface it! exposed, as indicated in Fig. 4, which is easily done in acenterless grinder, hardening of the surface I4 alone can be easilyaccomplished by a cyanide treatmentin well known manner. Thus thebearing surfaces of the roll interior and the head of the stud are madecapable of enduring long wear without rounding oif or wearing obliquely,a suitable lubricant being occasionally supplied, and wear of thejack-back by the boss is eliminated entirely or largely reduced, whilethe replacement boss is capable of being applied to and fixed in thejack lever in a very strong and secure manner by riveting it thereto.

The location of the bearing surface provided on the stud for the supportof roll I is important in reducing the work and cost of making the novelboss to practical levels. By making the retaining flange on the roll Iinstead of on the stud, and making the part of the stud which has thegreatest diameter serve as the bearing surface, the stripping of thissurface :4 in most economical manner by the precise and nearly automaticaction of a centerless grinder is made possible.

The neck portion 6 of stud 5 which intervenes between the head and theshank serves as a spacer permitting the stud to be drawn down againstthe surface of jack 8 to seat the interd vening radial shoulder 18 withthe requisite tightness against the face of jack 8, while leaving theflange 3 of roll I loose and free. That is, portion 6 of the stud hasgreater axial extent than flange 3 of the roll.

By making the annular retaining flange 3 on the roll very narrow, a widebearing surface M can be provided on the stud and thereby render theroll capable of supporting a heavier load through preventing theconcentration of wear on the outer rim or any one portion of the roll.

While I have illustrated and described a certain form in which theinvention may be embodied, I am aware that many modifications may bemade therein by any person skilled in the art, without departing fromthe scope of the invention as expressed in the claims. Therefore, I

. do not wish to be limited to the particular form shown, or to thedetails of construction thereof, but what I do claim is:

1. Areplacement boss for a part of the dobby motion of a loom comprisingin combination a relatively hard metallic roll having an annular flangeat one end, and a metallic stud for rotatably supporting the roll on thedobby part and retaining the roll by means of the rolls annular flange,the stud having a relatively soft metallic shank for riveting to thesaid part of the dobby motion.

2. A replacement boss for a dobby jack comprising in combination aheaded metallic stud having a relatively soft metallic shank integraltherewith for attaching the stud to the jack and a relatively hardbearing surface, and a relatively hard metallic roll rotatably mountedon the stud having an annular flange integral therewith retaining theroll on the stud by engagement under the latters head.

3. A replacement boss for a dobby jack having in combination a metallicroll having an annular flange at one end integral therewith, and ametallic stud provided with a head and a neck, the latter acting as aspacer spacing the head from the jack, such stud rotatably supportingthe roll and retaining the latter by means of the annular flange.

4. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange integraltherewith, and a metallic stud having an enlarged head and a reducedportion fitting within the flange and seating against a surface on thedobby jack, such stud rotatably supporting the roll and retaining thelatter by means of the rolls annular flange, and having a relativelysoft metallic shank for attaching the stud to the jack.

5. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange integraltherewith, a metallic stud having an enlarged head relatively hard atits periphery and a reduced portion fitting within the flange-andseating against a surface on the dobby jack, such stud rotatablysupporting the roll and retaining the latter by means of the rollsannular flange, and having a relatively soft metallic shank forattaching the stud to the jack.

6. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange integraltherewith, a metallic stud having an enlarged head relatively hard atits periphery and engaged by the roll, and having a reduced portionfitting Within the flange and seating against a surface on the dobbyjack, such stud rotatably supporting the roll and retaining the latterby means of the rolls annular flange, and having a relatively softmetallic shank for attaching the stud to the jack.

7. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange at one end of theroll integral therewith, and a metallic stud having an enlarged head anda reduced portion fitting within the flange and seating against asurface on the dobby jack, the head of such stud having a relativelyhard peripheral surface rotatably supporting the roll and retaining thelatter by means of the rolls annular flange, and having a relativelysoft metallic shank for attaching the stud to the jack. 7

8. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange integraltherewith, and a metallic stud having an enlarged head with a hardenedperipheral surface rotatably supporting the roll and retaining thelatter by means of the rolls annular flange, the stud having a softmetallic shank for attaching the stud to the jack.

9. A replacement boss for a dobby jack, having in combination, arelatively hard metallic roll having an annular flange integraltherewith, and a metallic stud having an enlarged head and a reducedportion fitting within the flange and extending therethrough seatingagainst a surface on the dobby jack, the head of such stud having arelatively hard peripheral surface in rotational engagement with theroll and retaining the latter by means of the rolls annular flange, andhaving a relatively soft metallic shank with a conical recess in itsextremity for attaching the stud to the jack.

EMIL C. JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,568,943 Amsden Jan. 5, 1926 1,841,923 Waters Jan. 19, 19322,368,007 Delahan et al Jan. 23, 1945 2,497,224 Laure Feb. 14, 19502,540,319 Bitzer Feb. 6, 1951 FOREIGN PATENTS Number Country Date536,704 Great Britain May 23, 1941 597,797 Great Britain Feb. 3, 1948

